Lemon posset got on our radar screens and captured our imagination when a group of us, volunteer sous chefs, got together and helped chef Amanda Cohen of Dirt Candy of New York City prepare dinner for 30 in Tuscany. Lemon posset with butternut squash was on the dessert menu. It is a classic English dessert that you’ll find in the repertoire of every English celebrity chefs, like Nigel Slater and Yotam Ottolenghi. The posset is catching on in the US lately. Popularity aside, what I’m most impressed is the science behind the three magic ingredients and the ease of preparation.
I made this for dessert last week away from my home kitchen while skiing. Needless to say, I had limited access to ingredients or equipments. I had to make do with something very basic. The posset came to mind. All you need are three ingredients (cream, sugar and fresh lemon juice or citrus acid), a stove and a refrigerator. I served the posset to some friends with rave review.
From the first bite to the last, the well-balanced, sweet-tangy flavor and the silky velvety texture really set this dessert apart. From the practicality viewpoint of a home cook, this recipe is godsend. No worry about tempering the eggs or using cornstarch, flour or gelatin to thicken the custard. Just follow this straightforward recipe and boil the cream for a few minutes to break down the milk proteins. Don’t be afraid to use heat. (Milk and cream can be boiled and reduced for hours.) Lemon juice increases the acidity of the cream to allow it to solidify.
Don’t think about reducing the amount of sugar or substituting cream with reduced-fat milk. I say that because that’s what I am most inclined to do. In this case, sugar and cream have critical roles to play in making this dessert luxurious, creamy and plush. Less sugar makes the posset thinner and looser. Cream has high fat content, which is necessary. We like creaminess. The smooth and seamless mouthfeel entices; it lingers in your mouth. Creaminess is a remarkable consistency, perfectly balanced between solidity and fluidity, between persistence and evanescence. I won’t change anything in this recipe.
For the science behind the magic of the posset, this is how American Test Kitchen explains it:
“When acid is added to milk (or when milk turns sour over time), the change in pH causes the milk’s casein proteins to lose the negative charge that ordinarily keeps them separate. Instead, they bond together in clusters, and the milk becomes grainy, or curdled. When acid is added to cream—which is a more viscous liquid than milk, thanks to its smaller amount of water and greater amount of fat (at least 36 percent fat as opposed to whole milk’s 3.25 percent)—the effect is different. The fat in cream outweighs the casein proteins 10 to 1 (in milk they are about equal) and so interferes with the proteins’ ability to form tight curds. As a result, a smooth, creamy consistency develops instead of a grainy one. Heating the cream for posset also has an effect: It causes the whey proteins in the dairy to unwind and attach themselves to the casein molecules and so helps stabilize the gelled liquid.”
Lemon juice, cream, and sugar practically make themselves into posset. Here’s how it works.
1. Lemon juice acidifies the cream, causing the casein proteins in the cream to clump.
2. Fat in the cream prevents the casein from clumping tightly; instead of curdling as milk would, the mixture thickens.
3. The sugar adds viscosity, giving the posset structure and a creamy texture.
Please visit and see other IHCC members’ takes on lemon recipes. Lemon is so versatile. I use lemon in everything besides cooking and baking. I love making a seriously sour lemon concoction that soothes when I have a sore throat. I deodorize my microwave oven with leftover lemons. The use of lemon is endless.